Punching Out a Preventive Maintenance Punch List
It seems things are built so well these days that we hardly think about maintenance until something goes wrong. However, when your livelihood and the livelihood of your employees depends on your printing equipment functioning properly, the onset of system failure is not the time to be thinking maintenance.
If you are in the business of converting certain types of films, foils, and even some papers into packaging, you know that before printing on any of these substrates, their surfaces must be treated in some way to improve their receptiveness to various inks, coatings, or adhesives. To ensure your surface-treating systems are working properly, a good preventive maintenance (PM) program is critical.
Designing your PM program
PM programs are by no means one-size-fits-all propositions. While there are components to any system that require regular checks, each shop will have its own set of unique circumstances that will affect surface-treating equipment. Converters should also consider specific applications in which the equipment will be used and the training of their equipment operators.
“Every converter has a unique situation that can affect the PM program, such as humidity, cleanliness, products that generate contamination of the [surface] treater, etc.,” says Lance Kimrey, Corona Designs. “The PM program should be designed to include the basic items, as well as the specific needs of the converter.” Such items include cleaning electrode insulators, the electrode discharge area, and the treater roll surface, as well as checking the ground brush and safety interlock switches.
According to Kenneth Klein, president and CEO of QC Electronics, Inc., “When developing a PM program, you must consider the environment the treater is operating in, the product the treater has running through it, and the amount of run time.”
Dennis Damon, eastern regional sales, Corotec Corp. concurs about the environment. “The environment [in which] the treater is located should dictate how often the system is inspected and cleaned,” he says. “This will consist of the plant air that is being drawn through the system. In extreme cases, a system will require attention every day, or it could be once a year if installed in a clean room.”
Tom Gilbertson, vice president, application engineering for Enercon, adds that environmental and climate factors can impact the need for more aggressive maintenance programs. “Dirty environments and locations with high humidity will require additional vigilance to keep systems working properly,” he says.
Finally, Robert Hablewitz, business unit manager, Pillar Technologies, emphasizes the importance of tailoring a PM program to specific applications. “Some applications are much cleaner than others,” he says. “As an example, in the case of an extrusion line running high-slip resin blends, cleaning is required more frequently. It will also be helpful to consider past failure history to determine what areas of the system should be focused on.”
Your program
Though treater station components are the most common components requiring replacement, there are several other common items that should be part of a PM program.
“On a daily basis, operators should visually inspect rolls, electrodes, and all insulators for general condition and cleanliness. Each week, power supply fans should be checked for proper operation. On a monthly basis, it is important to check and replace (as needed) ground roll brushes in order to keep the power supply running,” says Gilbertson.
“A PM list should include inspection of electrode surfaces to be sure they are clean and even,” says Klein. “Next is the roll surface. Check for buildup or roll coating damage. Airflow is another critical component to reliable treater operation. Make sure there is no blockage to your airflow, as blocked airflow causes excessive heat. More importantly, you can starve the corona of its much needed oxygen.”
Jeff Opad, co-owner of Jemmco, LLC, adds that the primary item on a PM list for corona treater is cleaning. “The process includes the production of heat. The result of this heat is the migration of film additives that can build up on the roller, in the ducting, and on the insulators. This buildup often has a lower burning point than the other components, which can produce carbon deposits that are conductive. This can often lead to arcing and premature component failure.”
PM—not difficult and benefits abound
Downtime reduction is probably the most important advantage of implementing a PM program. “The savings of a PM program are quickly seen through the reduction in downtime and replacement parts,” says Klein.
Opad concurs. “The bottom line is that the converter will experience less downtime and less waste due to unscheduled downtime because of the PM program,” he says. He adds that properly maintained equipment should last at least 15 years.
Kimrey contends that “the major advantage of a PM system is that major failures, such as roll coating failure, can be detected and repaired without disrupting production. [Eliminating the expense due to lost production] is the key.”
And why not implement the program? The advantages are obvious, and it’s not hard to do.
“Preventive maintenance is not difficult,” says Gilbertson. “But it does require a commitment from the company to make it part of its routine and culture. A successful preventive maintenance program initiative requires communication from upper management down through system operators.
Klein concludes, “The difference in having a PM program versus not is seen in maintenance budgets that range from hundreds of dollars with a program to thousands of dollars without a program. By investing a small amount of labor for cleaning time, a converter can run the corona treating system and depend upon it for reliable, quality corona treatment.” pP
What items should a preventive maintenance punch list contain?
According to Dennis Damon, eastern regional sales, Corotec Corp., the following consists of items worth considering.
First off, make sure the supply power to the system is shut off and locked out prior to inspecting any internal areas of the treating system.
Start with the power supply. Verify that its cooling fan is functioning. If an air intake filter is used, clean or replace it as needed. Visually inspect the interior for dust or dirt buildup, as this will cause components to run hotter than intended. Make sure no items have been placed near the cabinet that would restrict cooling airflow.
Next, visually inspect the high-voltage transformer for leaks or dirt. If the transformer is mounted separately from the treat station, inspect the high-voltage wire and standoffs inside the wireway for cleanliness and proper position.
Confirm that the exhaust source for the treating station is functioning properly. The exhaust serves two purposes: it removes ozone and it provides cooling air for the treat roll and electrode. Lack of airflow could cause premature dielectric failure or worse, allow ozone into the work environment. Ozone is very corrosive and could cause damage to other line components in the area of the treating station. If an ozone destruct canister is used, inspect the inlet filters and clean or replace as needed. Dirty filters will restrict airflow and may allow pollutants into the catalyst bed. If the catalyst gets contaminated, it could cost hundreds or thousands of dollars to replace depending on the size of the system.
The last item for inspection is the treatment station, but this would be the first place to look when troubleshooting. The inside of a corona treater is a very harsh environment. You have ozone, heat, and high voltage. Plus, you are constantly drawing plant air, along with any process particulates through the station. When dirt and/or moisture accumulate inside, you will have failures. Always check for cleanliness from the point the high voltage enters the station to where it connects to the electrode. Include any standoffs that may be holding the high-voltage wire in place. Then, inspect the electrode and electrode insulators. Remember that the insulators are the most common place for carbon trails to form. If the treat roll is dielectric covered, look for excessive wear that may indicate that the covering should be replaced. In addition to checking for cleanliness, all safety interlocks should be checked for proper operation.
